Lush is an object-oriented programming language designed
for researchers, experimenters, and engineers interested in
large-scale numerical and graphic applications. Lush is designed to
be used in situations where one would want to combine the flexibility
of a high-level, weakly-typed interpreted language, with the
efficiency of a strongly-typed, natively-compiled language, and with
the easy integration of code written in C, C++, or other languages.

Lush is Free Software (under the GPL license) and runs on GNU/Linux,
Solaris, Irix, and Windows under Cygwin.

Lush can be used advantageously for projects where one would otherwise
use a combination of an interpreted language like Matlab, Python, Perl,
S+, or even (gasp!) BASIC, and a compiled language like C. Lush
brings the best of both worlds by wrapping three languages into one:
(1) a weakly-typed, garbage-collected, dynamically scoped,
interpreted language with a simple Lisp-like syntax, (2) a
strongly-typed, lexically-scoped compiled language that uses the same
Lisp-like syntax, and (3) the C language, which can be freely mixed
with Lush code within a single program, even within a single function.
It sounds complicated, but it is not. In fact, Lush is designed to
be very simple to learn and easy to use.

If you do research and development in signal processing, image
processing, machine learning, computer vision, bio-informatics, data
mining, statistics, simulation, optimization, or artificial
intelligence, and feel limited by Matlab and other existing
tools, Lush is for you. If you want a simple environment to experiment
with graphics, video, and sounds,
Lush is for you.

Lush's main features includes:

A very clean, simple, and easy to learn Lisp-like syntax.

A compiler that produces very efficient C code and relies
on the C compiler to produce efficient native code
(no inefficient bytecode or virtual machine).

An easy way to interface C functions and libraries,
and a powerful dynamic linker/loader for object files or libraries
(.o, .a and .so files) written in other compiled languages.

The ability to freely mix Lisp and C in a single function.

A powerful set of vector/matrix/tensor operations.

A huge library of over 10,000 numerical routines,
including full interfaces to GSL, LAPACK, and BLAS.

A library of image and signal processing routines.

An extensive set of graphic routines, including
an object-oriented GUI toolkit, an interface to
OpenGL/GLU/GLUT, and the OpenInventor scene rendering engine.

An interface to the Simple Directmedia Layer (SDL)
multimedia library, including a sprite class with
pixel-accurate collision detection (perfect for 2D games).

This combination of flexibility, efficiency, and extensive libraries
with over 14,000 functions and classes makes Lush an ideal platform for
research and development in signal processing, image processing, machine
learning, computer vision, bio-informatics, data mining, statistics,
and artificial intelligence. Its speed and extensive libraries allow such
things as real-time sound, image, and video processing. Most users use
Lush as a research tool, but many use it as a general purpose script
language, or as a general language for application development. Some
have been known to use Lush to develop 2D and 3D games. A few have
even used Lush to develop commercial software for embedded processors.

IMPORTANT NOTE: New features and fixes are being added to the CVS
version of Lush on a daily basis. Before reporting a problem, please
install the CVS version.

Installation of the Debian/Ubuntu Package: As of December
2006, the maintainer of the Debian package for Lush is Yaroslav Halchenko (many thanks
to Yaroslav for volunteering). Until Yaroslav's recent involvement,
the Debian package was missing a few important dependencies. Yaroslav
has fixed them, so it should become considerably easier to install
Lush on Debian/Ubuntu and their many variations. Unfortunately, the
Lush version on Ubuntu 6.10 "Edgy" is still 1.1, and has many package
dependencies missing. So, until the next version, get the CVS version
(see below) or download and build the latest
released version.

Other Linux Distros: many commercial Linux distros
(Mandriva, Red Hat, Fedore Core, SuSE) have pre-packaged versions of
Lush. However, we strongly recommend that you install and compile the
CVS version if you are a serious user.

Downloading

CVS snapshot: if you want the bleeding edge version,
you can get a CVS snapshot as follows:

Released version: go to the download page,
download the latest version, and unpack the tar.gz

InstallingPre-requisites: On Debian/Ubuntu, you must install the
following packages: gcc, g++, libx11-dev, libinutils-dev, indent,
libreadline5, libreadline5-dev libgsl0, libgsl0-dev. On other
distros (Mandriva, SuSE, Fedora Core, etc), there are corresponding
packages with slightly different names.

Optional pre-requisites: Optionally, you can also install the
OpenGL development packages (freeglut3, freeglut3-dev,
libgl1-mesa-dev), SDL development packages (libsdl1.2debian,
libsdl1.2-dev), and BLAS/LAPACK (lapack3, lapack3-dev).

Compilation:

Then, compile Lush with:

cd lush
./configure
make

You can run Lush directly by typing wherever-you-installed-lush/bin/lush, or
by adding wherever-you-installed-lush/bin to your shell path.

However, you can also perform a system-wide install as follows:

su root
[type your root password]
make install

or (on Ubuntu):

sudo make install
[type your password]

This will install Lush and its libraries in /usr/local/share/lush
and the executable in /usr/local/bin/lush with a link from /usr/bin/lush.

Running
To start Lush, type "lush" at the prompt (and CTRL-D to exit).

Emacs users will prefer to run Lush within Emacs. To do so, add the
following line to your .emacs file:

(load "/usr/local/share/lush/etc/lush.el")

Then type "ALT-X lush" in Emacs to start Lush.

At the Lush prompt, type (helptool) to fire up the documentation browser.

NOTE:: on the old Mandrake 9.2, change the "-O3" to "-O2" in
the lush/src/Makefile or Lush may crash (due to some bug in gcc).

What is Lush?

Many software projects, particularly research projects,
require two languages:
an efficient compiled language such as C or C++ for implementing the low-level
or computationally expensive function, and a flexible, possibly interpreted
language for high-level control, scripting, experimentation, and tinkering.
Popular research-oriented interpreters such as Matlab are somewhat
inefficient, lack support for complex data structures, lack the
power of a full-fledged object-oriented programming language, and lack
simple interfacing to C and other compiled languages.

Lush uses a very simple Lisp syntax. If the word "Lisp" sends shivers
down your spine, be advised that the dialect of Lisp that Lush
implements is extremely simple to learn, with possibly one the
simplest syntaxes around. Most scientists, engineers, and
software developers who have learned Lush have become proficient at it
in a few days, even if they had no prior exposure to Lisp. It's very
simple. Really. In fact, Lush has been used to teach programming to kids.

The Lush compiler has several interesting properties, and a few limitations.
Its main advantage is that it generates very efficient C code which
is then compiled with the best available C compiler for the machine
considered and loaded dynamically. The C code produced does not simulate a
virtual machine, it is real, low-level, bang-the-metal, no-runtime-check,
don't-break-for-animals, C code, just like what you would write by hand.
Its main disadvantage is that, although it compiles a Lisp-like language,
it does no more for you than what a C compiler would (no automagic
memory management, no garbage collection, no functional programming).

real-time video edge detection using Video4Linux and SDL.

OpenGL animation.

A tour of the features

The Lush interpreter is written in C and features all the usual
functionalities and constructs found in every decent object-oriented
programming language such as conditional statements, loops, local
variables, functions, macros, objects, classes, methods, and
inheritance, but it also provides a large number of functions for
manipulating lists, strings, vectors, matrices, and tensors. String
functions include such things as regular expression matching and
substitutions.

This shows a simple lunar lander game that uses the SDL
library and the sprite class. The whole game fits in
60 lines of Lush.

The Lush interpreter is quite similar to some lisps of the mid 80's
like "Le_Lisp" and "UCI-Lisp". It is significantly simpler than
"Common Lisp" and quite different from Scheme.

An unusual feature of Lush is its compiler to C, its dynamic linker/loader,
and the ease with which one can interface existing C functions and
libraries. En even more unusual feature is the ability to intermix
Lisp and C source code within a single function.

The vector and matrix manipulation engine is quite powerful and
efficient, making Lush ideal for heavy numerical applications
and applications such as signal and image processing. It
includes functions to create, resize, and convert vectors, matrices,
and tensors with up to eight dimensions. It also includes basic
matrix operations such as scalar operations on all elements of a
matrix, dot products, outer products, transposition, highly optimized
1D and 2D convolutions. A set of vector/matrix iterators is also
provided.

Lush is an object-oriented language. Classes with slots and methods
can be defined and compiled. Derived classes inherit the slots and
methods of their parent class (similar to the C++ semantics).

Lush includes all the functions familiar to Lisp aficionados,
such as list functions, list iterators, physical list manipulation,
macros, splicing macros, symbol manipulation, etc, but most casual
users will probably prefer to stay away from those.

Lush provides a set of simple-to-use low-level graphic
functions to draw lines, polygons, rectangles, pictures, and text
in color, with automatic refresh and double-buffering capability (for
simple animations). Graphics can be drawn in an X-windows window (on
Unix), or sent to a PostScript file.

Lush also contains a very compact and easy-to-use object-oriented
graphical user interface generator called ``Ogre''. Ogre is entirely
written in Lisp on top of the low-level graphic functions mentioned
above. It contains predefined classes for buttons, sliders, radio buttons,
menus, string editors, etc... Ogre includes an automatic mechanism for placing
objects in the window, thereby greatly simplifying the design and
implementation of GUIs. Simple GUIs can be written in extremely short
times and are very compact. A very unique feature is that there is no
need to call an "event main loop": you can keep typing at the Lush
prompt while your GUI app is running!

Lush provides two models for Input/Output. One is a set of ``Lispy'' I/O
functions that allow easy input and output of ASCII data, lisp expressions,
lisp objects, and matrices. It includes such goodies as pipes and
sockets. The other model essentially provides access to the standard C I/O
library, including fopen, popen, fprintf, fscanf, fgetc, fputc fgets, and
various functions for reading and writing matrices.
Large matrices can be mapped in the virtual addressing space, instead of
explicitely loaded in memory. This allows to access very large datasets
efficiently.

This picture shows Lush's on-line documentation GUI. The right
pane shows an example of function that integrates Lush and C in the
same source. The C segment (shown in green) is delimited by the hash-brace
characters. Lisp variables can be refered to from the C by prepending
a dollar sign. Click on the picture for a full page screenshot.

A tour of the Lush Libraries

Lush has a huge collection of libraries and utilities available to the
user. Some are written in Lisp, some are written in C and interfaced
to Lush, others are pre-existing libraries that have been interfaced to
Lush.

For our numerically enclined friends, Lush has a full interface to the
GNU Scientific Library
(GSL, 3500 function), and to the
LAPACK and
BLAS Linear Algebra
libraries. This gives access to an extensive set of numerical and
statistical functions (several thousand in fact).

Lush includes a full interface to the industry-standard
OpenGL
library that allows the creation of 3D graphics and animations. This
interface include an interface to GLUT, OpenGLU, and
(coming soon) OpenRM
(scene graph rendering engine).
This makes Lush an excellent platform to write interactive
virtual reality applications, simulation software, and computer games.

Another popular library interfaced to Lush is the multimedia
and game APISimple Directmedia Layer (SDL).
It is enhanced by a high-level
library that allows the easy manipulation of sprites and animated,
movable screen objects with pixel-accurate collision detection.
This library, combined with Lush's simple syntax, makes it ideal
for developing simple video games and for teaching programming to children.

Lush contains a library of image processing functions to load, save,
resize and resample, warp, filter, and analyze images. Mathematical
morphology operations such as connected component analysis, distance
transform, erosion, and dilation, are also available for bitonal images.
It also includes classes and functions for easily grabbing video
using the Video4Linux API. It also includes an interface to the
Intel's
Open Computer Vision library (OpenCV).

Lush offers an extensive library for gradient-based machine
learning (which is the main research interest of the authors
of Lush). The list includes: neural networks (including
convolutional
neural networks), radial basis functions,
support vector machines, and many others. This library is based on an
innovative object-oriented design
that allows to build large learning machines out of multiple learning
modules and to train them cooperatively. Commercially used optical
recognition systems have been built with this library. Lush also
provides an interface to the popular
Torch package which includes
even more machine learning paradigms.

What's with all the frogs?
Well, Yann LeCun and Leon Bottou are both French, and many of the past
contributors have been French or French-speaking (Patrice Simard,
Yoshua Bengio, Patrick Haffner, Pascal Vincent).

Years of extensive focus groups studies and consultation with top
marketing experts convinced us that using an escargot would
send the wrong message for an allegedly fast language.

Also, frogs are very good at catching bugs.

Cute penguins and gnus were already taken, as well as the
numerous species found on the covers of O'Reilly books.

We like frogs. Really. Some of our best friends are frogs.
Particularly those accompanied by garlic and butter.[No Frog was physically harmed
in the making of this page, though we probably did hurt
their feelings.]

I want to get started, is there a good tutorial on Lush?
Have a look at this tutorial.

This site looks like a rip-off of the DjVuLibre site
Lush and DjVu were produced by
the same people (in fact Lush was used to prototype the first version
of DjVu). So, no rip-off, just laziness.
[This page is made entirely of recycled HTML tags]